I would like to see modern cam action tangs on their slip-joints, something that allows light opening and strong resistance to closing without needing a stronger spring. Spyderco, Boker, and Enzo all manage it with arguably less high tech folders. The rest of the Lion Steel slip joints are great, but the basic traditional square tang is a let down.
Textured G10 inserts on the Thrill would be good too, that is the slipperiest knife I have met, so easy for it to get away from you.